Flashback arrestor is a crucial safety device in gas welding and gas cutting operations. Below, I will explain in detail its application.
1，Core concept: What is tempering?
To understand the application of tempering preventers, one must first understand what “tempering” is.
Normal combustion: Combustible gases (such as acetylene, propane) are mixed with oxygen in the welding/cutting torch, sprayed from the nozzle and burned, and the flame is stable.
Tempering: This is a dangerous abnormal situation. The speed of flame combustion exceeds the speed of gas ejection, causing the flame to burn in the opposite direction of the fuel source along the gas pipeline. If not stopped, the flame will continue to burn into the regulator, hose, and even the interior of the gas cylinder, causing an explosion.
2，Application scenarios and installation locations
The tempering preventer must be used on all welding, cutting, heating and other equipment that uses combustible gas.
There are two main installation locations:
Export end (most commonly used and recommended): directly installed at the outlet of the pressure reducer of the gas cylinder or the outlet of the gas pipeline valve.
Advantages: Not only can it prevent the backfire flame from burning towards the pressure regulator and gas cylinder, but it can also protect the connecting hose. This is the most common and secure installation method.
(Schematic diagram: Gas cylinder ->Pressure reducer ->Tempering preventer ->Hose ->Welding and cutting torch)
Inlet end: Installed at the gas inlet of the welding and cutting torch.
Advantages: Provides the closest protection to the fire point, maximizing the protection of the hose.
Disadvantages: The preventer itself may be more susceptible to damage (such as bumps, splashes) due to its proximity to the working point, and it cannot protect the hose between the preventer and the gas cylinder. This method is now less common.
Mandatory application scenarios:
All acetylene cylinders must be equipped with flashback arresters.
At centralized gas supply stations with pipeline gas supply, flashback arresters must be installed on each output pipeline.
Mobile gas welding and cutting operation vehicle.
The ignition gas system for industrial boilers and kilns.
3. Important precautions to be taken:
Merely installing correctly is not enough, it must also be used and maintained correctly:
Cannot be mixed: flashback arresters for different gases such as acetylene, propane, and natural gas are specialized and cannot be interchanged. Because their design pressure and the size of the gaps in the flame retardant components are determined based on the explosive characteristics of specific gases.
Installation direction: There is an arrow on the tempering preventer indicating the direction of gas flow. During installation, it is necessary to ensure that the arrow points in the direction from the gas source to the welding torch. Incorrect installation will result in complete failure.
Regular inspection and replacement are required:
Check sealing: Regularly inspect the preventer for air leakage.
Check resistance: If the flame becomes smaller or the gas supply is not smooth, it may be due to internal blockage of the preventer.
Regular replacement: Temper arresters are not permanent equipment. Once tempering occurs, or according to the manufacturer’s recommendations (such as annually) or working hours, it must be replaced immediately. Because the internal flame retardant components may have been sintered or damaged, they may not be effectively flame retardant when tempering occurs again.
Cannot be dismantled: It is extremely dangerous to dismantle the backfire preventer without authorization because it is perceived as “gas consuming” or “affecting firepower”.